Boiler tube shield



March 11, 1941. E BAERER 2,234,222

BOILER TUBE SHIELD Filed Oct. 28, 1939 INVENTOR.

fi v'jezz'e A Bw arer,

I ATTORNEY.

Patented Mar. 11, 1941 UNITED STATES BOILER TUBE SHIELD Eugene A. mercy, Ridgefield, N. J.

Application Octoberv 28, 1939, Serial No. 301,706

2 Claims.

This invention relates to improvements in boiler tube shielding means for cooperation with soot blowers with which the boiler is equipped.

vIn tubular boilers, wherein the hot products 5 of combustion are circulated along and about the tubes through which the waterfrom whichsteam is to be generated is passed, the exterior surfaces of the water tubes are exposed to accumulation of soot thereupon which, if not removed, soon obstructs the transfer of heat through the tube walls to the contained water, thereby considerably impairing the efiici-ency of the boiler. To avoid this, means have been employed for blowing soot accumulations off and away from the Water tube surfaces, so that the soot is carried away through the draft system of the boiler. Such soot blowers usually comprise rotatable blower elements into which .dry, high pressure steam is delivered to be discharged from lateral nozzles or ports with which said elements are provided. The steam thus discharged fromthe nozzles of the blower elements provides high veloci-ty blasts which contact the water tube surfaces so as to dislodge and sweep away the accumulations of soot therefrom. Both the soot and the products of combustion circulating through the boiler contain a considerable amount of fly ash and other like hard gritty particles, which, when caught up and propelled by the high 3() velocity steam blasts discharged by the blower elements, are caused to impinge upon the water tube surfaces with abrading or sand-blast like efieot thereupon. This abrasion and resultant wear, unless guarded against, may greatly reduce ,35' the useful life of the water tubes to the extent of requiring replacement thereof long before their break down would otherwise be normally expected.

To guard boiler tubes against wearing attrition 40 of soot blowing steam blast-s, shield devices have been externally applied to the boiler tubes at points where exposed or subjected to more or less direct or substantially head-on impingement thereof. by said blasts. In the most commonform heretofore provided, such shields have merely comprised cylindrical sheet metal plates or bands applied to encircle desired areas of the boiler tubes to be protected. These bands are either discontinuous or made in half sections provided 5 at their meeting ends with radially projecting flanges secured together by bolts, whereby the bands are retained in encircling attachment to the boiler tubes. Such form of shield device is very awkward to manipulate when applying or remov- 55 ing the same relative to the tube, especially when the tubes are closely spaced or grouped; furthermore, owing to the projection of the radial flanges thereof away from the boiler tube sides and out of direct contact with the comparatively 60 cool walls of the tubes, said flanges are subjected to the unrelieved high heat of the hot products of combustion flowing through the boiler, whereby the same are frequently fused together, rendering removal of the shield extremely .diflicult when it may be desired to removeand r'enew,,.5 the same.

Having these things in mind, my present .invention has for an object to provide .asimple, eflicient and easily manipul-atable boiler .tube shield device, wherein the means for securing the ;-l-0 same in service position upon a boilertube comprises compact and close lying cooperating couplingyelements with which the shield bodyand its attachment strap are provided, together with removable wedge key means forinterlockingcoopl5 erating coupling elements in shield securinga'ttached relation to a boiler tube; allwhereby. said coupling elements and cooperating wedgekey are maintained comparatively cool by close contact with the relatively cool boiler tube so asto. be 20 free from tendency to fuse together. i Another object of the invention is toprovid in combination with a boiler tube shield. and.at tachment strap therefor, coupling means for uniting these parts in operativeassembledrel-ation which is very easy to actuatein either applying or removing the shield from a tube, especially-in close quarters, i. e. in installations where the tubesare closely grouped and working space consequently verylimited. 5

Other objects of this invention, not at this time more particularly enumerated, Willbe understood from the following detailed description of the same.

An illustrative embodiment of theinvention is 53 shown in the accompanying drawing, in which: Fig. l is a fragmentary sectional view of .a portion of a boiler equipped with soot blowing apparatus, and showing tubes. of the boilerhaving applied-thereto protective shield devices made 4 according to this invention.

Fig. ,2 is an enlarged side elevation of the novel .shield device of this invention .as applied tofa boiler tube; Fig. 3 is a top plan orfaceyiew of the same; Fig. 4 is a sectional View through thei'4' 5 same, taken on line 44 in Fig. 2; and Fig. 5 is a fragmentary perspective 'viewof. parts of the coupling means for uniting the'elementsofthe shield device.

Similar characters of reference are employed in the above described' views, to-indicate corresponding parts.

Referring to Fig. 1 0fthe drawing,ythereference character .10 indicates the wall of au-boiler structure, and H the water tubes which extend through the interior of said boiler structure. The reference character I2 indicates the me ans mounted eX-teriorly of the boiler wall Illthrough which high pressure steam is supplied towsoot blower elements l3 which project into the boiler 0 f faces of the strap member. The inner marginal goo blowing blasts emanating from the blower element I3, comprises, a shield plate or body I5 of suitable peripheral shape, as e. g. of the oval shape shown-in Fig, 3, and of curvilinear contour sub-j "stantially conformable to the curved external j'surface of a tube 1 Ito which said shield plate or body is to be applied. Integrally formed therewith to project outwardly from opposite marginal sides of said plate or body I5, are laterally spaced legs or tongues I6 providing an intermediate indentingspace I1. Said legs or tongues I6 are provided'with thickened extremities adapted to pro- 'vide coupling bosses I8 somewhat raised or stepped up from the external face surfaces of the legsor tongues I6. The'inner marginal sides of said'bosses I8 are shaped to provide undercut shoulders I9. Cooperative with said shield plate or body I5 is an attachment strap member 20 which is bowed to a 'curvature substantially conformable .to the curved external surface of a tube II to which the shield device is to be applied. Integrally formed therewith to project outwardly and endwise respectivelyfrom the opposite extremities of said attachment strap member 20 are legs or tongues 2I. Said legs or tongues 2| arelikewise provided with thickened extremities adapted to provide coupling bosses 22 somewhat r'aised'or stepped up from the external face sursides of said bosses 22 are shaped to provide undercut shoulders 2'3. Said legs or tongues 2| 7 are of widths somewhat less than the widths of the indenting spaces I'I intermediate the legs or tongues, of said shield plate or body I5.

1 Said shield plate or body I5 and its cooperative attachment strap member 20 when operatively assembled, are so dimensioned circumferentially to fit more or less snugly in encircling relation to andaround a tube II to which they are to be applied. When the shield plate or body and attachment strap member are assembled together around a tube II. the endwise projecting legs or tongues 2| of the latter enter the indenting spaces I'I lying between the legs or tongues I6 of the opposed ends of the former so as to interlap 'saidlegs or tongues 2| and legs or tongues I6, and

so as to bring the coupling bosses I8 of the'latter into opposed staggered relation to the coupling bosses 22 of the former. When the parts of the shield devices are thus arranged tapered wedge keys are driven across and between the op-' posed coupling bosses I8 and 22 so as to engage the undercut shoulders I3 and 23 thereof. ()wing to the tapering wedge shape of the keys 24, the same, when driven home, operate to draw the opposed ends of the shield plate or body I5 and attachment strap member 20 together, thus constricting the shield device circumferentially so as to bind the same in firm close hugging relation to the tube I I embraced thereby, thus firmly and securely holding the shield device against disn cement from the area of the tube to which it is applied, and which is desired to be shielded or' protected thereby. If desired, the sides of the wedge keys 24 may be chamfered, as at 2'5, to correspond and conform tothe formation of the undercut shoulders of the coupling'bosses with which they are engaged; thus so interlocking these parts that all risk, of lateral outward dis placement of the key wedges is avoided.

As shown in Fig. 1 the shield devices (which a whole are indicated by the reference letter S applied thereto in said Fig. 1) are applied to and so located on desiredtubes II as to cover areas thereof which are opposed more or less directly to head-on impingement of the steam blast, discharged from the nozzles or ports I4 of the blower element I3. v j

It will be obvious that the shield plate or body I5 and cooperating attachment strap member 28,

when mounted on the tube I I in close hugging'reg lation thereto, will so contact the same as to readily and quickly transfer the heatabsorbe'd from the hot products of combustion to which they are exposed to the comparatively cool water tube II; and since the coupling bosses I8-'22 are I also in flat lying close contact with the comparatively cool tube II, likelihood of fusing, softening or deformation thereof is avoided. f

Owing to the low or close lying disposition of the coupling bosses and wedge keys in parallel relation to the sides of the tube It, adequate to clearance space between adjacent tubes is assured for access to these devices whenlocking up'or releasing the same, and consequently the shield devices may be more easily and conveniently manipulatd for application to or removal from a 3'5 tube II.

Having described my invention, I claim; 1. A boiler tube shield device for cooperation with soot blowing apparatus comprising,"ajuniformly thin and fiat lying arcuate shield pla'te'of "40 thickened transverse coupling bosses, and 'a flat removable key device for engagementqbetween opposed couplingbosses, thus providing. shield fastening means closely contiguous to the tube surface and of minimum projecture therefror'n.v m 2. A boiler tube shield device for cooperation" with soot blowing apparatus comprising, a uniformly thin and fiat lying arcuateshield plate. of suitable peripheral shape adapted .to snugly engage the external surface of a tube'to which it is applied, a separable and correspondingly uniformly thin arcuate attachment strap member likewise adapted to snugly engage the tube surface, said plate and strap member having at opposed portions thereof interfitting tongues extending in the planes thereof" and provided at' their extremities and in the planes thereofwith slightly thickened transverse coupling bosses, said'bosses having inwardly facing undercut shouldersiand a removable tapered wedge key for engagement across and between the shoulders of opposedTO bosses, thus providing shield fastening means closely contiguous to the tube surface and of minimum project'ure therefrom.

EUGENE A. Banana. 

